Torpedo control



Aprii 1947. w. H. SMITH 2,419,173

TOHPEDO CONTROL Filed July 28, 1943 3 Sheets-Sheet 1- WITNESSES: D 44 INVENTOR W 4. Wa/fer/iJm/ffi.

t, 77 a Ml,

April 15, 1947. w, $M|TH 2,419,173

TORPEDO CONTROL Filed July 28, 1943 3 Sheets-Sheet 2 iii WITNESSES: INVENTOR ATTORNEY April 15, 1947. w. H. SMITH 2,419,173

TORPEDO CONTROL Filed July 28, 1943 3 Sheets-Sheet 3 \AQTNESSES: INVENTOR m. Wa/ker/iSm/ffi.

BY W5, W

ATTORN EY Patented Apr. 15, 1947 UNITED STATES PATE'NT 2,419,173

HTORPEDO CONTROL Walter'H. Smith, "Wilkinsburg, Pan, assignor to Westinghouse "Electric CorporationfEastPitts- "burgh, 'Pa.,'-a corporation of Pennsylvania Application July 28, 1943, Serial;No. 496,415

.13 Claims.

Myinvention. relates toasystem of, control, and more particularly .to. a control: for controlling the operation of 'a conveyance as, 'for example, a

.torpedo.

.The .priorart type of torpedoes are usually driven .by a turbine operated from compressed .air. .Asthe .pressureinthe flasks decreases, the

.efiiciencyof the turbine .is very materially deereased and also the speed drops off considerably so .that .the -speed of the torpedo over its entire run variesLfromalhigh speed'to .a rela- .tively low speed. Such speed .variation of the .torpedo very materially affects the firing accuracy -and also effectsthe vrange over whichlany accurate .shots might be made.

The;pr.esent .War brought into use theall-elec- .tric torpedoes. However, all-electric torpedoes mayvhavethe .same disadvantage-since it is well .known that a storage battery, whether itbea primary battery or asecondarylbattery, very mapletely exhaustedregardless of the variation in .the terminal, pressure. orpoten'tial of .theibattery orothersource of energy.

.Anothenobject. of my .invention is ltheprovision of means for maintaining'the speed of .an electric propulsion motor-of a torpedo constant over .the entire run. o'f-the torpedo regardless of variations in voltage of the supply.

.-.A.more specific object of my 1 invention .is the provision of means for .controllinglthe speed "of a motor without. any. hunting .of the controlme'ans.

The foregoingobjects are merely illustrative of the object.dfmyinvention, and otherob'jects and advantages .will become readily apparent from a study of the following specification andthe appended olaims and the accompanying drawings,

in .which:

:Figure 1 .isla somewhat .schematicshoWing of .an electrically propelled torpedo provided with .my-invention,

Fig.2 is also a somewhat zschematicshowing of .my-invention; illustratingathe .theory .of operation of my" system of control. for maintaining constant motor speed;

Fig. 3 shows a .plurality of curves .to 'facilitate the disclosure of my invention,

dis :a. modified showing of my. invention :Figs5. is amendview of .the propulsionmotor, Fig.6 is,- azside view-of-the .propulsionrmotor, Fig.1! isva-side wiewlof atdetailoi myinvention;

.IEig. B-Lis allongitudinal sectional .view, along Fig. 9 vLis .-.a transverse sectional view on line ..IX-IX..of llig. 7; and

Figs. 9, .10; 1.1,:12andil3 -are.transverse sectional viewsoimo'dified showings of certainvalve structures .embodiediin; my invention.

Reierringmore particularly to Fig. 1 or the drawings, I designates .a torpedo Ltubes'hOWn in .section, .with the .torpedo 2 itself vshown v,sec-

.seriesttype motomand is .-provide'cl, "forlthepurpose of conserving space, with .a radial commutator Brand 'aQbru'sh shiftingiring 9 for.con- .trolling :the, speed of -the, motor.

The use of. a series motor 'foritorp'eilo fpropulsion is a.novel. combination. lIn a'torpedm'space is at. a .premium. With a series 'motor'no fstarting control is needed,'the 'commutating poles .can

be eliminated, the conductors are allheavie'r and stronger. and thusnot s0 readily'subjectfto damage upon firingof thejtorjpedo. The'foreg'oing novel results, aidingin'thereliability of'the serv ice. andconserving space, :are illustrativebut not exhaustive of the advantages of "the series 'motor for Itorpedo propulsion.

'fiI'he" brushlshifting' mechanism is betterish'own in.Figs. "5 and "6 "where l0 indicates the motor framejinoluding the poles of the magnetic circuit,'8 designates theradial'type commutatorand *9 is a rin of insulating material (see'lFig."6) ,"carrying the brushes as and I2. For purposesnf clarity in describing my invention, I'I 'show only .two brushes but in the actual installation *the machine hassix miles. There mayghoweverjbe aconsiderable-number of pairs of poles. All jof the brushes .are .mounted to be rotated 'with'the ring 9. .fDlsposed iatith'e end of the motoris "the spider ll.3;w'hic"h notonlymositi'ons thering"9"with reierenceto thelmotor shaft,,but,alsoh'as mounted thereon. the governor mechanismgenerallydes- .ignatedb 'l4.

"Thegovernor mechanism. is one of the unique features of my 'inventionand .tojsuitablyioperate the {governor mechanism th'efmotor "shaft is .priovide'd with" bevel jgear f5 operating the bevel 3 provided with a longitudinal channel l8 and end enlargements |9. Pivoted at 20 and 2| on the enlargements H) are bell crank levers 22 and 23. These bell crank levers are provided with diskof liquid emitted at the outlet opening is dependent upon the axial position of the shaft 21 and thus upon the area of registry of the aperture 42 withrtheinlet and outlet openings. Fur-. thermore, the slower the speed the longer will be the period of time for each revolution that the registry will be maintained. From this it will be apparent that a liquid supplied under pressure to the inlet opening 4|?- will be emitted in short spurts like rollers 24 and 25 which coact with a diskat the outlet opening 4| only when the speed of like member 26 keyed to the shaft or valve stem the motor has decreased to a given value and the 21. The disk-like member 25. is provided with a length or the quantity of each emission will be a diametrieal slot, as shown in Fig. 4, just wide function of the amount of such decrease in speed. enough to loosely receive the disk-like rollers 25. The value of this will appear more clearly here- The disk-like member 26 engages the thrust bearinafter. ing 28 of the ball bearing type, and thus provides As shown in Fig. 9, only one registry may occur for free rotation of the shaft 2'! but no rotation for each revolution. However, since some appliis imparted to the outer race of the ball bearcations may require that a greater quantity of ing 28 and thus no rotation whatsoever to the liquid be transmitted, it may be desirable to utiannular member 29. lize apertures in the shaft 21 as shown in either The depending portions of the bell crank levers Fig. 10, Fig. 11, Fig. 12 or Fig. 13. In Fig. 10, two are each provided with threads as shown which spurts of liquid will be transmitted for each revcarry nuts 30 and 3|. These nuts are provided olution, namely, each time that the shaft has with threads of such nature as to be binding on rotated through only 180. In Fig. 11 two outthe depending portion of the bell crank lever, let openings are shown and the apertures in the and, therefore, are not caused to shift axially shaft 21 are displaced at 120 of each other, three on the depending portion except when positively discharges will thus occur for each revolution adjusted by means of a wrench. It will thus be of the shaft 21. Fig. 12, where two perpendicapparent that the nuts 30 and 3| act as the fly ularly intersecting apertures are shown, four poles of a governor whose effective moment arm discharges of liquid will take place at the outlet may be adjusted by axially adjusting the nuts. openings for each revolution of the shaft. In The annular member 29 is provided with a practice the outlet openings are combined into shoulderfor receiving the compression spring 32. a single outlet tube. In Fig. 13, where three inter- The degree of compression of this spring may secting apertures are shown 60 apart, six dis- -be just d by urni g the nut 3 on the threa d 30 charges of liquid will take place at the outlet V sleeve-like stem 34 of the bearing 39 for the shaft openings for each revolution of the shaft.

By e adjusting nut 33 y fi e Speed To gain a better understanding of my invention justments y be Obtained With y g0Vern0r-- it may not be amiss to discuss the showing in Figs. Further, the adjustment can be carried out dur- 2 and 3, respectively. In Fig. 3, curve 43 indiing motor operation. This is illustrated in Fig. 4 35 cates how the battery voltage varies with its deand to still better advantage in Where the gree of discharge and if the rate of discharge is graduation 35 may represent one speed, graduaknown, the curve may be plotted against time, ,tion 36 another speed, whereas intermediate as shown in Fig. 3. Curve 44 shows how the despeeds may be read off by the graduations 31 magnetizin component of the armature current in coaction with the longitudinal index 38. For of a series motor may be varied by shifting the instance, graduation 35 may represent the speed brushes in such a direction as to increase the of 900 R. P. M., 35 the speed of 1200 R. P. demagnetizing component. If the voltage, therewhereas the graduations 31 may, depending upon fore, supplied to a series motor changes, as inthe position of the nut, indicate speeds intermedicated by curve 43, and the demagnetizing comdiate' the speeds of the main graduations. ponent can be varied as shown by curve 44, then The bearing 39 for shaft 21 is provided with an it is apparent that some optimum rate of change i inlet opening 40 and an outlet opening 4| and of brush position may be obtained so as to obtain coa'cting with these openings, respectively, I proa constant speed for the motor. Curve 45 individe apertures in the shaft 21. In Figs. 4, 5, '7, cates the speed variation of the type of motor 8 and 9,v I show only one opening as 42 through Iutilize with my system of control.

the shaft 21. As will be apparent from an in- It will be noted that the speed remains conspection of Figs, 8 and 9, one portion of the openstant from time n to time is. The speed then ing 42 is of a larger diameter than the other. drops oiT to zero. This simply means that at the 1 However, this is not particularly significant exregion 46 the battery is very nearly completely I ceptthat in the process of manufacturing, it is exhausted and there is no possibility of extractjmore convenient to control th size of the apering further sufiicient energy from it to operate I ture, namely, the small portion of it if the porthe motor. Normally, in torpedo operation it is ltionat right angles to it as shown in Fig 9 is reldesirable to at least obtain a constant speed for ativ'ely' large. the torpedo for about 50 seconds or some other From the foregoing description, it will be apsimilar time period. parent that as the speed of the motor varies the In Fig. 2, the brushes on the ring 9 are shown shaft 21 rotates directly proportional to the m0- as disposed in the position that would normally tor speed and its axial position is also governed be called the neutral position. In this position, directly proportional to speed. From this it will conductor turns 41, 48 and 49 produce some debe apparent that if fluid or a liquid, as oil under magnetizing component but if during operation, pressure, is supplied to the inlet opening 40, it will means are provided for shifting the ring 9 in a l only emerge at the outlet opening 4| if the apercounterclockwise direction to such a position as ,ture 42 is in alignment with the inlet opening to make the additional conductor turns 50, 5|, 52 and outlet opening, and this can only occur at a and 53, demagnetizing turns, then it is apparent predetermined speed. Furthermore, the quantity that the flux of the motor is decreased and its speed will thus be increased. It i not my aim, however, to rotate th ring 9 counterclockwise haphazardly over the entire range just mentioned, but to do so insmall steps depending upon the tendency of the motor speed to drop. =Fl'1rther,

in actual use many "more turns. are involved ;so :that a finer speed control isuobtained than would Lbepossible if no more thdllnCOl'ldHOtOl'SoTiO 53, .inclusive,-werelinvolved.

Todully understand-this, let it be assumedthat .thetorpedo 1 is in" the position shown in Fig. land is'then fired .by'the usualmethodsused tofire :torpedoes. In so doing, the dog 54 inthe torpedo rtube: operatesthe lever .55 which actuatesa valve or'a trigger switch 56. Assoonas this=valve-56 J-is operated, the air .under compression in .the 1' flask 51 is allowed to flow-'toapluralityoflmechanisms onthe torpedo to operate them .but for "my purpose it is i-sufiicientto knovvithat the .air .under pressure also 'actuates the pneumatic switch 58. This switch 58 may be operateddirectly bylever'55 and-no air flask is needed.

:As .soon as this switch 2581s actuated, a.circuit is :1 established from the ,positive terminal of the 5 battery through the .limit switch 59, pneumatic :netic switch fil tothe negative terminal of the Floattery. The electromagnetic switch 6| immediately operatesclosing the contact members62, thereby establishing anenergizing circuit. for the series motor, as shown-in Fig. :2, and thismotor immediately comes up to speed and the governor xmechanismzimmediately opens-the contact members :63.

the motor operates at the-constant speed eelected by the suitable adjustments made on the .governormechanism, namely, the adjustments of nuts 39,131 and the adjustment of thecompres- .sion of spring 32.by the nut 33 (see Fig. 4) contact members 63 remain'open but as. soon as the -speed decreases by a slight amount from that selected, contact membersJi-3 close and a circuit -isthen established from the positive treminal of the battery through the pilot motor 64, governor switch-.63 tothe negative terminal of the battery.

In actualpractice, the governor switch is seclose with the least amount of axial change of -position of shaft 21. Thismeans that any small departure. from the speed slected will cause operation of thepilo-t motor 64 to shift the rack 65 engaging the. lever arm on'the ring:-9 Thering 9 is thus shifted counterclockwise, and since a small movement orishift of the brushes immediately effects the speed correction desired, the

governor switch again opens and pilot motor 64 is stopped. In actual operation, the brush is at first shifted but very .slowly by infrequent intermittent operation of the pilot motor 64 and as the battery becomes more and more discharged,

the frequency and time periods of operation of motor 54 become larger and the brushes are thus shifted faster until the battery is substantially completely discharged and the voltage collapses to some low value and the speed decreases. The

limit switch59 is so positioned that the circuit for the battery is opened and noserious damage may thus be caused to the battery.

.For the showing in Figs. 4 to 13, inclusive, a

hydraulic speed control is used, and for this type of operation the governor does not actually opcrate a switch but operates the valve mechanisms herein'before discussed. When the hydraulic mechanism is used, firing of :the torpedo again causes the operation of the lever .55 and the valve "56, but in this instance the high pressure air in addition to operating the switch 58 is admitted to the upper portion of the reservoir 16.

'iThis reservoir .16 is "filled .witha isuitable .oil (not shown) below the piston 56, which ipiston *sSWitCh"58, the actuating coil 60: of the: electromag- 240 I :lected tobe of the snap acting type to open and is:held in its upperpositionby :the.=.liquid disposed below it. Thepiston is provided -with suitable -sea1ing.ring-61 and a-sealing cup-calmadehfla .synthetic :rubber that .is :non-reactive with i the zoiliused. When the air pressureris admitted-to :-the :reservoir, the piston '66 will :tend-to move to'expelthe oilifrom the reservoir butno liquid can be expelled from the reservoinexcept when the speed of the motor is below agpredetermined .value. When lthis 'occurs, liquid :is itransferred ..from the .reservoir through .tube v59 to .the :inlet openingvMJ-eand from there.- to :the .outletzopening 4 i. -:-As the liquid is :emitted in spurts afrom Jthe accurately machined .opening, -:it moves through -the .conduit ill to the hydraulic 'brush :shifting mechanism IH Thisbrush shifting :mechanism ll .iseadjust- .ably:mounted on the spider :[3 :and includes .a plunger =l12 for -ithe; piston head 13. This gpiston head -.'l3=is provided with asuita'ble sealing -.cup 3:14 i of synthetic' rubber nonreactive with i the oil so thatunoliquid can leak-,past=the;piston. .lI'he .plunger 12*engages apin 15 on -.the -.rin,g-.- 9,:.and .as the speed varies, the plunger l2 moves .the ring 9 counter-clockwise to shiftvthabrushes. ?It iwill thusbe apparent that thefgreater c-the' tendency: of the speed change, the faster will ;.plunger .12 move. The fundamental action,-.therefore,-.of plunger :72 -is substantially the tsamel as uthe rack --shown inFig. 2. 'In :one'.case,'a pilot ,motor operates the ,ring .9, whereas .in the second: case ..a-hydraulic mechanism operates the ring .9,-.but the changecffectedonthe ringail is=alike.in.each

case.

.Oneof -.the unique features, however, *of .my hydraulic system? is, there is no possibility. ofany hunting of .the governing mechanism. One of the main reasons no hunting can take place is that the li uidzislemitted-inshortspurts and .there is :.thus no opportunity whatsoever L of .de- 'velopingqanyrinertia of motion in the parts, and :inconsequencethe ring 9 carrying thebrushes willhold exactly the position-it isrcalled'uponto hold by the, governing: mechanism.

-While -I have disclosed two embodiments ;of

.my invention, namely, onespecies-of an electric type and another of a'hydraulic type,.Idonot wish .to 'be limited to the particular combina- .tions.shown, but wish to'be limited onlyby'the scope. of the claims hereto appended.

:I' claim as myinvention:

1..A system of controllfor an EIGOU'iCflHYgPIO- pelled conveyance, in combination, .an electric "bat-tery providinga source of direct current, a direct current propulsion motor 1 connected ,to the batteryfor propelling the conveyance, said motor having excitingpoles and windings thereon'connected to the battery, and control means operable as a function of ethe motor speed :and the battery voltage for progressively decreasing the effective excitation of the field windingjust .-sufiiciently -to compensate for the decrease in battery voltage with the-degree of'discharge-cof .thebattery .to thus .maintain the motor .speed constant'up ,tonear complete exhaustion of-the battery.

2. .In a system ofcon-trol for an electrically propel-led conveyance, in combination, an :elecvtrio battery providing a source .of direct cur- .rent, a direct current propulsion .motorof-the .series type connected to the battery for propel- ..ling;the.:conveyance, said motor having exciting .pol esand' windings. thereon. connected to the .bat- .tery,.'and=control means operable as -=a:funct-ion rof ttheimotor :speed :and the battery voltage.- for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the effective excitation of the field winding just sufficiently to compensate for the decrease in battery voltage with the degree of discharge of the battery to thus maintain the motor speed constant up to near complete exhaustion of the battery.

3. In a system of control for an electrically propelled conveyance, in combination, a conveyance, a battery of a given capactiy, a direct-current motor of the series type connected to the battery and coupled to propel said conveyance, said motor being provided with a commutator and brushes mounted on a rotatable ring for shifting the brushes circumferentially of the brushes from one position to another position, and means responsive to the motor speed for progressively shifting said ring and thus the brushes circumferentially of the commutator from the one position to the second position to thus progressively increase the demagnetizing component of the armature current whereby the motor speed is maintained constant up to near complete discharge of the battery.

4. In a system of control for an electrically propelled conveyance, in combination, an electric battery providing a source of direct current, a direct current propulsion motor connected to the battery for propelling the conveyance, said motor having exciting poles and windings thereon connected to the battery, and control means operable as a function of the motor speed and the battery voltage for progressively decreasing the effective excitation of the field winding just sufficiently to compensate for the decrease in battery voltage with the degree of discharge of the battery to thus maintain the motor speed constant up to near complete exhaustion of the battery, said control mean comprising a valve stem connected to rotate in proportion to the motor speed and a governor mechanism for shifting the valve stem axially in proportion to changes in motor speed, a bearing sleeve within which the valve stem rotates and slides, fluid inlet means and fluid outlet means in the bearing sleeve, a source of fluid under pressure for supplying fluid to the inlet means, aperture means of a given cross sectional dimension in the valve stem so positioned that the sectional area of registry with emitted per spurt being thus a function of the angular velocity of the valve stem and the axial position of the valve stem, and means responsive to the total quantity of fluid thus emitted for effecting the said progressive decrease of the effective excitation of the field windings, f the motor.

5. In a system of control for an electrically propelled conveyance, in combination, an electric battery providing a source of direct current, a direct current propulsion motor of the series type connected to the battery for propelling the conveyance, said motor having exciting poles and windings thereon connected to the battery, and control means operable as a function of the motor speed and the battery voltage for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the effective excitation of the field winding just sufficiently to compensate for the decrease in battery voltage with the degree of discharge of the battery to thus maintain the motor speed constant up to near complete exhaustion of the battery, said control means comprising a valve stem connected to rotate in proportion to the motor speed and a governor mechanism for shifting the valve stem axially in proportion to changes in motor speed, a bearing sleeve within which the valve stem rotates and slides, fluid inlet means and fluid outlet means in the bearing sleeve, a source of fluid under pressure for supplying fluid to the inlet means, aperture means of given cross sectional dimensions in the valve stem so positioned that the sectional area of'registry with the inlet means and outlet means is a function of the departure of the motor speed from a selected speed, whereby fluid will be emitted from the outlet means in small spurts the quantity of fluid emitted per spurt being thus a function of the angular velocity of the valve stem and the axial position of the valve stem, and means responsive to the total quantity of fluid thus emitted for efiecting the said progressive shifting of said brushes to thus effect said decrease of the effective excitation of the field windings of the motor.

6. In a system of control for an electrically propelled conveyance, in combination, an electric battery providing a source of direct current, a direct current propulsion motor connected to the battery for propelling the conveyance, said motor having exciting poles and windings thereon connected to the battery, and control means operable as a function of the motor speed and the battery voltage for progressively decreasing the effective excitation of the field winding just sufliciently to compensate for the decrease in battery voltage with the degree of discharge of the battery to thus maintain the motor speed constant up to near complete exhaustion of the battery, said control means comprising a stem connected to shift axially in proportion to changes in motor speed, a bearing for the stem, a switch operated to close by the axial shift of the stem upon changes in speed of the motor, a pilot motor energized by the closure of said switch, and means operated by said pilot motor for effecting said progressive decrease in the efiective excitation of said propulsion motor.

'7. In a system of control for an electrically propelled conveyance, in combination, an electric battery providing a source of direct current, a direct-current propulsion motor of the series type connected to the battery for propelling the conveyance, said motor'having exciting poles and windings thereon connected to the battery. and control means operable as a function of the motor speed and the battery voltage for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the efiective excitation of the field winding just sufiiciently to compensate for the decrease in battery voltage with the degree of discharge of the battery to thus maintain the motor speed constant up to near complete exhaustion of the battery, said control means comprising a stem connected to shift axially in proportion to changes in motor speed, a bearing for the stem, a switch operated to close by the axial shift of the stem upon changes in speed of the motor, a pilot motor energized by the closure of said switch, and means operated by said pilot motor for efiecting said progressive shifting of said motor brushes to thus efiect said decrease motor.

81 In a" system of control for an" electrically propelled torpedo; in combination; a torpedo; a battery offagiven capacity in" the torpedo for providing; a" source of direct-current energy, a direct current torpedo-propulsion motor; means for-connecting the motor to the battery at' the moment the torpedo" is fired, said motor having exciting poles and windings thereon also connected to'"the battery at the moment tlie'torpedo'is fired, and control means operable-as a function" of the motor speed and the battery voltage for progressively decreasing the effective excitation of the field winding just sufliciently to compensate for the decrease in battery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to near complete discharge of the battery.

9. In a system of control for an electrically propelled torpedo, in combination, a torpedo, a battery of a given capacity in the torpedo for providing a source of direct-current energy, a diroot-current torpedo propulsion motor of the series type, means for connecting the motor to the battery at the moment the torpedo is fired, said motor having exciting poles and windings thereon also connected to the battery at the moment the torpedo is fired, and control means operable as a function of the motor speed and the battery voltage for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the eifective excitation of the field Winding just sufficiently to compensate for the decrease in battery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to near complete discharge of the battery.

10. In a system of control for an electrically propelled torpedo, in combination, a torpedo, a battery of a given capacity in the torpedo for providing a source of direct-current energy, a direct-current torpedo propulsion motor, means for connecting the motor to the battery at the moment the torpedo is fired, said motor having exciting poles and windings thereon also connected to the battery at the moment the torpedo is fired, and control means operable as a function of the motor speed and the battery voltage for progressively decreasing the effective excitation of the field winding just sufiiciently to compensate for the decrease in battery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to complete discharge of the battery, said control means comprising a valve stem connected to rotate in proportion to the motor speed and a governor mechanism for shifting the valve stem axially in proportion to changes in motor speed, a bearing sleeve within which the valve stem rotates and slides, fluid inlet means and fluid outlet means in the bearing sleeve, a source of fluid under pressure for supplying fluid to the inlet means, an aperture of given cross sectional dimensions in the valve stem so positioned that the sectional area of registry with the inlet and outlet means is a function of the departure of the motor speed from a selected speed, whereby fluid will be emitted from the outlet means in small spurts the quantity of fluid emitted per spurt being thus a function of the angular velocity of the valve stem and the axial position of the valve stem, and means responsive to the total quantity of fluid thus emitted for effecting the said progressive decrease of the effective excitation of the field windings of the motor.

11 In a systenr of control for "an" electrically propelled t'orpedo, in combination; a'torpedo; a battery of a given capacity in'the torpedofor providing a source of direct-current energy, a direct-current torpedo propulsion motor'of the series type, means for connecting the'motor to the battery at the moment the torpedois fired, said motor having exciting po-lesand windings thereon also connected to the-battery at'the moment the torpedo is fired, and'control means operable' as a= function-ofthemotor speed and the battery voltage for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the effective excitation of the field winding just sufficiently to compensate for the decrease in bat tery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to near complete discharge of the battery, said control means comprising a valve stem connected to rotate in proportion to the motor speed and a governor mechanism for shifting the valve stem axially in proportion to changes in motor speed, a bearing sleeve within which the valve stem rotates and slides, fluid inlet means and fluid outlet means in the bearing sleeve, a source of fluid under pressure for supplying fiuid to the inlet means, an aperture of given cross sectional dimensions in the valve stem so positioned that the sectional area of registry with the inlet and outlet means is a function of the departure of the motor speed from a selected speed, whereby fiuid will be emitted from the outlet means in small spurts the quantity of fiuid emitted per spurt being thus a function of the angular velocity of the valve stem and the axial position of the valve stem, and means responsive to the total quantity of fluid thus emitted for effecting the said progressive shifting of said brushes to thus eifect said decrease of the effective excitation of the field windings of the motor.

12. In a system of control for an electrically propelled torpedo, in combination, a torpedo, a battery of a given capacity in the torpedo for providing a source of direct-current energy, a direct-current torpedo propulsion motor, means for connecting the motor to the battery at the moment the torpedo is fired, said motor having exciting poles and windings thereon also connected to the battery at the moment the torpedo is fired, and control means operable as a function of the motor speed and the battery voltage for progressively decreasing the efiective excitation of the field winding just sufficiently to compensate for the decrease in battery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to complete discharge of' the battery, said control means comprising a stem connected to shift axially in proportion to changes in motor speed, a bearing for the stem, a switch operated to close by the axial shift of the stem upon changes in speed of the motor, a pilot motor energized by the closure of said switch, and means operated by said pilot motor for efiecting said progressive decrease in the effective excitation of said propulsion motor.

13. In a system of control for an electrically propelled torpedo, in combination, a torpedo, a battery of a given capacity in the torpedo for providing a source of direct-current energy, a direct-current torpedo propulsion motor of the series type, meansfor connecting the motor to the battery at the moment the torpedo is fired, said motor having exciting poles and windings 11 thereon also connectedto the battery at the moment the torpedo is fired, and control means operable as a function of the motor speed and the battery voltage for progressively shifting the motor brushes to produce a demagnetizing component by the motor armature current for decreasing the effective excitation of the field winding just sufficiently to compensate for the decrease in battery voltage with the degree of battery discharge to thus maintain the speed of the torpedo constant up to near complete discharge of the battery, said-control means comprising a stem connected to shift axially in proportion to changes in motor speed, a bearing for the stem, 2, switch operated to close by the axial shift of the stem upon changes in speed of the motor, a pilot motor energized by the closure of said switch, and means operated by said pilot motor for effecting said progressive shifting of said motor brushes to thus efiect said decrease in the 10 effective excitation of said propulsion motor.

WALTER H. SMITH. 

